Integrating a nanoscale-size material realizes expression of a novel function. Therefore, integration techniques and integrated structures are now remarkable techniques and materials.
For example, metal nanoparticles having a particle size of from 1 to 100 nm can generate local light (hereinafter, near-field light) of which the size correspond to the radius of the particle. Accordingly, a metal nanoparticle array structure where metal nanoarrays are two-dimensionally arrayed on a substrate in such a manner that the distance between the metal nanoparticles could be from 1 to 10 nm can generate a large electric field or an extremely high-intensity near-field light in the gaps between the metal nanoparticles.
The metal nanoparticle array structure is expected to be applicable to optical waveguides, photochemical reactors, optical devices, high-sensitivity sensors and catalysts. For these applications, it is necessary to use a metal nanoparticle array structure where the size and the shape of the metal nanoparticles and also the distance between the metal nanoparticles are well uniformly controlled, for which, therefore, well controlling the size and the shape of the metal nanoparticles and also the distance between the metal nanoparticles will be a technical key point.
Some reports have already been made relating to the technique of producing a metal nanoparticle array structure. For example, nanosphere lithography (Non-Patent References 1 to 3) and electron beam lithography (Non-Patent Reference 4) are already-existing techniques, which, however, have some problems in that the lithography apparatus is expensive and a large-scale structure is difficult to produce.
Production according to a self-organizing method has been tried. As a method of using an external pressure, there are known a Langmuir method (Non-Patent References 5 to 8), a Langmuir-Blodgett method (Non-Patent References 9 to 10), a dip coating method (Non-Patent Reference 11), use of solid-liquid interface (Patent Reference 1). As a method of using an external field, there are known an electrophoresis method (Non-Patent Reference 13, Patent Reference 3), and a solvent evaporation method (Non-Patent Reference 12, Patent Reference 2). However, these methods do not have any strong immobilizing means such as chemical bond or the like between the metal nanoparticle array structure and the immobilizing substrate, and are therefore problematic in that the metal nanoparticle array structure would readily peel away from the immobilizing substrate.
Regarding the technique of note for fixation on a substrate such as chemical bond or the like, there are known a thiol bond (Non-Patent References 14 to 15), a CN bond (Non-Patent Reference 16), and a coordination bond (Non-Patent References 17 to 18). According to these methods, however, a metal nanoparticle array structure having a high coverage is not obtained.
The coverage means the proportion of the area occupied by the metal nanoparticle array structure within a specific area.
Accordingly, at present, a metal nanoparticle array structure, in which the size and the shape of the metal nanoparticles and also the distance between the metal nanoparticles are well uniformly controlled and which is firmly immobilized on a substrate via chemical bond or the like and has a high coverage, is not as yet attained technically.    Patent Reference 1: JP-A 2006-192398    Patent Reference 2: JP-A 2007-313642    Patent Reference 3: JP-A 2009-6311    Non-Patent Reference 1: Wang, W.; Wang, Y.; Dai, Z.; Sun, Y.; Sun, Y. Appl. Surface Sci. 2007, 253, 4673-4676.    Non-Patent Reference 2: Shen, H.; Cheng, B.; Lu, G.; Ning, T.; Guan, D.; Zhou, Y.; Chen, Z., Nanotechnology, 2006, 17, 4274-4277.    Non-Patent Reference 3: Tan, B. J. Y.; Sow, C. H.; Koh, T. S.; Chin, K. C.; Wee, A. T. S.; Ong, C. K., J. Phys. Chem. B 2005, 109, 11100-11109.    Non-Patent Reference 4: Felidj, N.; Aubard, J.; Levi, G. Appl. Phys. Chem. 2003, 82, 3095-3097.    Non-Patent Reference 5: Liao, J; Agustsson, J. S.; Wu, S.; Schoenenberger, C.; Calame, M.; Leroux, Y.; Mayor, M.; Jeannin, O.; Ran, Y.-F.; Liu, S.-X.; Decurtins, S. Nano Lett. 2010, 10, 759-764.    Non-Patent Reference 6: Chiang, Y.-L; Chen, C.-W; Wang, C.-H.; Hsein, C.-Y; Chen, Y.-T; Appl, Phys. Lett., 2010, 96, 041904-1-041904-4.    Non-Patent Reference 7: Kim, B.; Tripp, S. L.; Wei, A. J. Am. Chem. Soc. 2001, 123, 7955-7956.    Non-Patent Reference 8: Kim, B.; Sadtler, B.; Tripp, S. L. Chem. Phys. Chem., 2001, 12, 743-745.    Non-Patent Reference 9: Park, Y.-K.; Yoo, S.-H.; Park, S. Langmuir, 2008, 24, 4370-4375.    Non-Patent Reference 10: Brown, J. J.; Porter, J. A.; Daghlian, C. P.; Gibson, U. J. Langmuir, 2001, 17, 7966-7969.    Non-Patent Reference 11: Dai, C.-A.; Wu, Y.-L.; Lee, Y.-H.; Chang, C.-J.; Su, W.-F. J. Cryst. Growth, 2006, 288, 128-136.    Non-Patent Reference 12: Wang, H.; Levin, C. S.; Hales, N. J. J. Am. Chem. Soc., 2005, 127, 14992-14993.    Non-Patent Reference 13: Peng, Z.; Qu, X.; Dong, S. Langmuir, 2004, 20, 5-10.    Non-Patent Reference 14: Kaminska, A.; Inya-Agha, O.; Forster, R. J.; Keyes, T. E. Phys. Chem. Chem. Phys., 2008, 10, 4172-4180.    Non-Patent Reference 15: Grabar, K. C.; Smith, P. C.; Musick, M. D.; Davis, J. A.; Walter, D. G.; Jackson, M. A.; Guthrie, A. P.; Natan, M. J. J. Am. Chem. Soc., 1996, 118, 1148-1153.    Non-Patent Reference 16: Chan, E. W. L.; Yu, L. Langmuir, 2002, 18, 311-313.    Non-Patent Reference 17: Wanunu, M.; Popovitz-Biro, R.; Cohen, H.; Vaskevich, A.; Rubinstein, I. J. Am. Chem. Soc., 2005, 127, 9207-9215.    Non-Patent Reference 18: Zamborini, F. P.; Hicks, J. F.; Murray, R. W. J. Am. Chem. Soc. 2000, 122, 4514-4515.    Non-Patent Reference 19: Hartling, T.; Alaverdyan, Y.; Hille, A; Wenzel, M. T.; Kall, L. M., Optics. Express, 2008, 16, 12362-12371.    Non-Patent Reference 20 Raffa, P.; Evangelisti, C.; Vitulli, G.; Salvadori, P. Tetrahedron Lett, 2008, 49, 3221-3224.